This invention relates to a method for the preparation of multiple gauge metal strip by a shaving operation wherein the strip workpiece is drawn through the shaving apparatus.
In many applications, such as the production of copper strip for the formation of electrical connectors and the like, it is necessary to provide a multiple gauge thickness in the metal strip. Heretofore, such conventional procedures as continuous milling have been employed to produce the desired variations in gauge. Such processes suffer from the disadvantages of being time-consuming and generating an unfavorable form of scrap.
Another procedure which has been investigated in the art comprises the reduction to gauge by a rolling operation. Rolling operations in production are unfavorably restricted to certain shapes, tend to involve complex and costly tooling and are not good enough to provide products meeting commercial tolerances and that are free from structural defects.
The technique of shaving as a form of metal reduction has been known for some time, however its application has been generally limited to the finishing of materials of uniform cross section by the reduction in cross sectional area of the workpiece, with reduction conducted along the entire surface area thereof. This technique is illustrated in U.S. Pat. No. 3,055,102 to Shaw et al., wherein a shaving tool is applied against a rod or bar which reduces cross sectional area along the entire surface thereof.
Certain problems would appear to arise if the shaving technique exemplified by Shaw et al. were to be directly applied to the manufacture of multiple gauge products from rectangular strip stock. Specifically, the application of shaving force against only a portion of the total surface of the strip tends to magnify some of the problems set forth in the aforenoted patent, particularly, the inability to hold the workpiece properly centered with respect to the tool, with the result that the workpiece wanders and a wavy or broken surface may result. A further difficulty which is believed to be magnified by the removal of stock from only a portion of workpiece surface relates to the excessive chattering and longitudinal vibration that takes place as the strip passes through the tool, which appears on the finished product as a galled or torn surface. Finally, the uneven application of frictional stress to the workpiece can result in unwanted product uneveness or camber, which would require subsequent processes to eliminate.